Electroacoustic transducers are now widely used in many commercially important and industrial applications. Included among these uses are seismic oil exploration, ship navigation, loudspeaker components, medical massage, vibratory oil recovery from shale, and chemical waste and emulsion separation. Scientists and researchers have continually improved the efficiency of these devices, but low frequency, low mechanical Q transducers have proven especially difficult to design.
Modern transducers often utilize the piezoelectric effect for converting electrical energy to acoustic or sonic energy. The piezoelectric effect, now well known and well understood, is a property of certain ceramic and other materials. When such a material is properly configured, an electrical charge causes it to distort.
An alternating current applied to the material produces mechanical vibrations, in turn producing acoustic waves. Conversely, a piezoelectric element can serve as an acoustic or sonic detector or receiver, converting received acoustic energy to electrical pulses.
Piezoelectric elements, therefore, are especially well-suited to form the vibratory driving elements in electroacoustic transducers. The resonant frequency and amplitude of the transducer's output is determined by such factors as the choice of construction materials, the dimensions of the transducer, the type of piezoelectric crystal chosen and the input signal amplitude.
It is quite important for many applications that the transducer be reasonably compact and sturdy. They are often used in the field, under water and in locales where repair or replacement is not possible.
A particularly important use of electroacoustic transducers is the treatment of chemical wastes and the dispersal of emulsions. One of the initial steps in waste disposal and recycling is the removal of water from the solid waste constituents. Acoustic energy has proven useful for this, as well as for removing solid particles from filters and screens. Similarly, the breaking up of water-oil emulsions, as occur in oil spills, can be achieved through the application of acoustic energy. Substantial power outputs are required for applications such as these, however, which has not previously been available from these devices.
Conventional transducer technology is represented and explained in numerous prior art patents, such as U.S. Pat. No. 4,651,044, to Komanek; U.S. Pat. No. 4,076,617, to Bybel; and U.S. Pat. No. 2,812,252, to Harris. Many of the above-described applications for transducers are explained in these and other patents.